The increasing concern over anthropogenic underwater noise and its environmental impact has motivated the search for effective strategies to mitigate tip-vortex cavitation in marine propellers. This work investigates the physical mechanisms governing its formation and identifies pressure-side-oriented, smoothly tip-raked geometries as a promising mitigation approach. Medium-fidelity Reynolds-averaged Navier–Stokes simulations are employed to build a surrogate model, with tip rake and its radial evolution as design variables and hydrodynamic efficiency and the Lamb vector divergence as metrics of cavitation intensity and hydro-acoustic performance. Low-fidelity optimization loops serve as an efficient tool to rapidly explore the design space and identify physically meaningful geometries while reducing computational cost by over 98% relative to conventional fluid dynamics simulations. High-fidelity, scale-resolving simulations with dynamic mesh adaptation validate the physical findings, showing that pressure-side tip bending suppresses the primary tip vortex, attenuates secondary vortical structures, and preserves the quasi-steady sheet cavity. These modifications achieve broadband sound pressure level reductions of up to 20 dB in the 200 Hz–8 kHz range without compromising hydrodynamic efficiency. Overall, the study highlights the critical role of tip-vortex physics in underwater noise generation and demonstrates that multi-fidelity frameworks provide an efficient means to derive acoustically optimized propeller geometries, contributing to the reduction of environmental noise impact.
Portillo-Juan et al. (Mon,) studied this question.